Slubbing Machine with an Arrangement for Detecting and Removing Yarn Flaws

ABSTRACT

The invention relates to a slubbing machine for producing a rove ( 1 ) from a fiber web ( 2 ), wherein the slubbing machine has at least one spinning nozzle ( 3 ) with an inlet opening ( 4 ) for the fiber web ( 2 ), wherein the spinning nozzle ( 3 ) is assigned at least one air nozzle through which the air can be channeled into the spinning nozzle ( 3 ) in order to impart a protective rotation to the fiber web ( 2 ) within the spinning nozzle ( 3 ), wherein the spinning nozzle ( 3 ) has an outlet ( 5 ) through which the rove ( 1 ) can be drawn out of the spinning nozzle ( 3 ), and wherein the slubbing machine comprises at least one receiving device ( 28 ) arranged downstream of the spinning nozzle ( 3 ) in the transport direction of the rove ( 1 ), particularly in the form of a winding device ( 6 ) to receive the rove ( 1 ) leaving the spinning nozzle ( 3 ). The invention proposes that the slubbing machine comprises an arrangement ( 7 ), to be passed by the rove ( 1 ), for detecting and removing yarn flaws ( 8 ), the arrangement ( 7 ) being placed between the outlet ( 5 ) of the spinning nozzle ( 3 ) and the receiving device ( 28 ). The invention further discloses a method for producing a rove ( 1 ) from a fiber web ( 2 ) using a slubbing machine, which is characterized in that, after leaving a spinning nozzle ( 3 ), the rove ( 1 ) passes an arrangement ( 7 ) for detection and removal of yarn flaws ( 8 ), which is placed between the outlet ( 5 ) of the spinning nozzle ( 3 ) and a receiving device ( 28 ), wherein by means of the arrangement ( 7 ), yarn flaws ( 8 ) are detected upstream of where the rove ( 1 ) is received, and are removed from the rove ( 1 ).

The invention relates to a slubbing machine for producing a rove from afiber web, wherein the slubbing machine has at least one spinning nozzlewith an inlet opening for the fiber web, wherein at least one air nozzleis assigned to the spinning nozzle through which air nozzle the air canbe channeled into the spinning nozzle in order to impart a protectiverotation to the fiber web within the spinning nozzle, wherein thespinning nozzle has an outlet through which the rove can be drawn out ofthe spinning nozzle, and wherein the slubbing machine comprises at leastone receiving device arranged downstream of the spinning nozzle in thetransport direction of the rove, particularly in the form of a windingdevice to receive the rove leaving the spinning nozzle. In addition, amethod for producing a rove from a fiber web using a slubbing machine isproposed, wherein the fiber web is introduced into a spinning nozzlethrough an inlet opening, wherein, using an air flow, a protectiverotation is imparted to the fiber web within the spinning nozzle,wherein the rove can be drawn out of the spinning nozzle through anoutlet and wherein the rove leaving the spinning nozzle is receivedusing a receiving device, for example a winding device, arrangeddownstream of the spinning nozzle in the transport direction of therove.

The production of rove (coarse roving) using a slubbing machineconforming to this type is already known. Thereby, in principle, a fiberweb fed to the spinning nozzle, in a vortex chamber of the spinningnozzle, is exposed to a selected air flow. Thereby, the air flow isdirected to the fiber web in such a manner that the outer ends of thefibers forming the fiber web are pulled to some extent from the web andultimately wrapped around the remaining, untwisted core area of thefiber web. In this manner, a rove is received that, despite a strengthincreased compared to the fiber web, still features a certain capabilityof being drafted, such that, in a subsequent textile machine (forexample, a ring spinning machine), it can be drafted using a draftingsystem, i.e. homogenized.

With such a production of rove, the fact that yarn flaws (i.e., sectionsof the rove, the physical parameters of which, such as diameter,length-related weight, density, strength, etc., are outside definedlimits) cannot be ruled out is disadvantageous. However, such flaw spotsrepresent blemishes in the rove, which cannot be completely remediedeven using a drafting system of the subsequent textile machine.

The task of the present invention is to propose a slubbing machine or amethod for producing a rove, with the assistance of which a rove of thehighest possible quality can be produced.

The task is solved by a slubbing machine and a method with thecharacteristics of the independent claims.

In accordance with the invention, it is proposed that the slubbingmachine includes an arrangement to be passed by the rove, for detectingand removing yarn flaws, wherein the arrangement is placed between theoutlet of the spinning nozzle producing the rove and the receivingdevice downstream of the spinning nozzle in the conveying direction ofthe rove. Thereby, the receiving device may be designed, for example, asa winding device, with the assistance of which the rove drawn out of thespinning nozzle can be spooled onto a coil, in order to be able to feeda downstream textile machine at a later point in time. Alternatively, itis also conceivable to design the receiving device as an intermediarycomponent which feeds the produced rove, without an interposed spool,directly to the downstream textile machine. In such an event, it isconceivable, for example, to design the receiving device as a(preferably driven or drivable) pair of rollers, with the assistance ofwhich the rove can be collected and selectively fed for its further use.

In any event, the invention provides that the device for the detectionand removal of a yarn flaw is assigned to the slubbing machine, suchthat yarn flaws are immediately removed after the production of the roveon the slubbing machine itself (if the slubbing machine has two or morespinning nozzles, it is advantageous if a separate device for thedetection and removal of a yarn flaw is assigned to each spinningnozzle). Thus, a subsequent rewinding for the purposes of the removal ofyarn flaws is no longer necessary. Rather, the slubbing machine deliversan error-free rove, which can be further processed without additionalintermediate steps.

For the detection of the yarn flaw, optical sensors or ultrasonic,microwave or other sensors suitable for the detection of a yarn flaw canbe used. The sensors are preferably connected to a control unit, whichalso may be connected to components of the slubbing machine and/or itsdrives (more specifically described below), in order to control therespective rotational speeds and/or conveying speeds.

It is advantageous if the arrangement comprises, in addition to a devicefor the detection and a device for the removal of the yarn flaw, a yarnaccumulator for the interim storage of the rove leaving the spinningnozzle during the removal of the yarn flaw. Thereby, the yarnaccumulator is preferably placed between the outlet of the spinningnozzle and the device for the removal of the yarn flaw. The yarnaccumulator has, for example, a drivable coil bobbin, in order to loopthe rove around several times, starting from a first front side, anddraw it out again in the area of a second front side. If the coil bobbinturns with a circumferential speed equivalent to the delivery speed ofthe spinning nozzle, the filling level of the yarn accumulator remainsconstant (the quantity of the rove taken from the yarn accumulator isequivalent to the quantity of rove dispensed again). If a yarn flaw isnow detected by the device for the detection of a yarn flaw, thereceiving device (for example, in the form of the specified windingdevice) is stopped in such a manner that the section with a yarn flawcomes to a stop in the device for the removal of the yarn flaw, and theyarn flaw can be removed from the yarn. In such an event, through theyarn accumulator, it is possible that the spinning nozzle still producesrove that can now be stored in the yarn accumulator on an interim basis.After the removal of the yarn flaw and the linkage of the ends of theyarn that arose upon the removal, the receiving device is once again putinto operation. If the receiving speed is selected so high that moreyarn is received than that produced by the spinning nozzle, the yarnaccumulator gradually empties. After reaching a defined filling level,the receiving speed is once again adjusted to the production or deliveryspeed of the spinning nozzle, such that the filling level of the yarnaccumulator is once again constant.

It is also advantageous if the yarn accumulator is placed between thedevice for the detection of a yarn flaw and the device for the removalof the yarn flaw. In such a case, the device for the detection of theyarn flaw may be arranged, for example, immediately after the outlet ofthe spinning nozzle, such that yarn flaws can be detected as early aspossible. Thereby, the receiving speed (i.e., the quantity of rove thatwill be received by the receiving device) may be gently throttled tozero, since the section of the rove featuring the yarn flaw must stillpass a certain distance until it comes to a stop inside the device forthe removal of the yarn flaw.

It is also advantageous if a first conveying device for the rove isarranged between the outlet of the spinning nozzle and the yarnaccumulator, and a second conveying device for the rove is arrangedbetween the yarn accumulator and the device for the removal of the yarnflaw. In particular, it is thereby advantageous if the conveying speedof the second conveying device is adjustable independent of theconveying speed of the first conveying device. If a yarn flaw is to beremoved in the device for the removal of the yarn flaw, the secondconveying device may be stopped, while the first conveying devicecontinues to draw out rove from the spinning nozzle and deliver it tothe yarn accumulator. If necessary, the two conveying devices may bedesigned, for example, as a pair of rollers, wherein the rove may passthe pair of rollers between each corresponding roller and, when therollers are at a standstill, may be kept in place by them in a clampingmanner.

It is also advantageous if the yarn accumulator is placed between thefirst conveying device and the second conveying device. Thereby, thefirst conveying device serves the purpose of drawing out the rove duringand after the removal of the yarn flaw, while the second conveyingdevice downstream of the yarn accumulator serves the purpose of, whileit is at a standstill, fixing the rove locally and thereby holding theyarn flaw in the device for the removal of the yarn flaw.

As a general matter, it must be stated here that the device for theremoval of the yarn flaw preferably has a cutting or separating unit,with the assistance of which the rove is able to be severed before andafter the yarn flaw. An additional device is also integrated, with theassistance of which the ends of the yarn that arose after the cutting ofthe yarn flaw can be linked together again. For example, a linkingthrough a rubbing, needling or calendering process is conceivable. Airjets can also be used to achieve the link, with the assistance of aselected air flow.

Particular advantages are entailed if a pneumatic yarn accumulator isused, which accumulator is designed to suck the rove produced during theremoval of the yarn flaw into a recess. Preferably, the negativepressure prevailing in the recess can thereby be controlled. It is alsoconceivable that there is a constant negative pressure, such that the(otherwise sagging) section of the rove drawn out from the spinningnozzle that is not received by the receiving device (for example,because a yarn flaw is removed) is always sucked from the yarnaccumulator into the recess. The recess may have a screen on which therove is placed, wherein the screen separates the recess from asubsequent vacuum line.

Advantages are also entailed if the slubbing machine comprises a controlunit that is designed to continue to operate the first conveying deviceduring the removal of the yarn flaw, and to abort the conveying of therove using the second conveying device. In such an event, the productionof the rove may take place continuously, even if the rove leaving thespinning nozzle has a yarn flaw, which must be removed from the rove. Ifthe second conveying device stops, the rove drawn out of the firstconveying device is stored in the yarn accumulator on an interim basis.After the removal of the yarn flaw, the second conveying device and,with it, the receiving device, is once again put into operation usingthe control.

It is advantageous if the slubbing machine includes a control unit thatis designed to stop the receiving of the rove carried out using thereceiving device during the removal of the yarn flaw, and resumes afterthe removal of the yarn flaw. In such an event, the rove may be freed ofexisting yarn flaws in the device for removing a yarn flaw, withoutcausing an unwanted tear of the rove after the specified device.

It is also advantageous if, after leaving the spinning nozzle, the rovepasses an arrangement for the detection and removal of yarn flaws placedbetween the outlet of the spinning nozzle and the receiving device,wherein, using the arrangement, yarn flaws are detected prior toreceiving the rove and removed from the rove. Preferably, a slubbingmachine with one or more of the preceding characteristics is therebyused. For the respective advantages, reference is made to the previousdescription.

In this connection, it is advantageous if the rove is severed after thedetection of a yarn flaw using a device for removing the yarn flaw,before and after the yarn flaw, and the section featuring the yarn flawis led away. In addition, it should be provided that the remaining endsof the yarn (i.e., the sections of the rove adjacent to the originallyyarn flaw) are linked back together after the removal of the yarn flaw.The link takes place, for example, using a known splicing procedure orusing air currents, which can achieve the link or a convergence of thefibers of the ends of the yarn.

It is advantageous if the production of the rove continues during theremoval of the yarn flaw, wherein the rove produced during the removalof the yarn flaw is stored on an interim basis using a yarn accumulatorarranged between the outlet of the spinning nozzle and the device forthe removal of the yarn flaw. In such an event, the spinning nozzle maycontinuously produce rove, while the rove produced upon the linking ofthe ends of the yarn that arose upon the removal of a yarn flaw isstored on an interim basis until the yarn is received by the receivingdevice (for example, in the form of a winding device).

It is also advantageous if the rove is drawn out of a spinning nozzleusing a first conveying device and fed to the yarn accumulator, anddrawn out of the yarn accumulator using a second conveying device andfed to the device for the removal of a yarn flaw. The first conveyingdevice ensures that the rove continuously produced by the spinningnozzle is led away, while, when necessary, the second conveying devicecan be halted, in order to allow for the removal of a yarn flaw. Thesecond conveying device may fix, in a clamping manner, the rove alsoduring the removal of the yarn flaw, such that an unintentional movementis prevented.

It is also advantageous if the first conveying device continues duringthe removal of the yarn flaw with the drawing out of the rove from thespinning nozzle, while the conveying of the rove using the secondconveying device is interrupted. In such an event, the yarn accumulatortakes the rove produced by the spinning nozzle, and releases it againafter the removal the yarn flaw or the subsequent linking of the ends ofthe yarn.

It is particularly advantageous if the receiving of the rove using thereceiving device is stopped during the removal of the yarn flaw andresumed after the removal of the yarn flaw. In such an event, a tearingof the rove that is stopped during removal in the area of the device forthe removal of the yarn flaw can be prevented. After removal, thereceiving device and, if present, the second conveying device, are onceagain put into operation, wherein it is preferable that startup occurssynchronously.

It is also advantageous if a winding device is used as a receivingdevice, wherein the length of the rove stored on an interim basis usingthe yarn accumulator is held within defined limits using a control unit,by increasing the spooling speed of the winding device upon exceeding anupper limit and decreasing the spooling speed upon falling below a lowerlimit. This prevents an overflow of the yarn accumulator or a tearing ofthe rove. If the second conveying device described above is presentbetween the yarn accumulator and the receiving device, its conveyingspeed at the spool device is also adjusted, in order to prevent atearing or excessive sagging of the rove in this area. However, inprinciple, the second conveying device may also be omitted if therotational speed of the coil is controlled in such a manner that thefilling level of the yarn accumulator (regardless of a cleaner cut thatmight have occurred) is always kept within the specified limits. In suchan event, the slubbing machine in accordance with the invention has onlythe described first conveying device, since the drawing out of the rovefrom the yarn accumulator is realized using the winding device. For thispurpose, the winding device preferably has a drive roller for the coil,the rotational speed of which is adjustable, depending on the fillinglevel of the yarn accumulator. Alternatively, as this is self-evident, ashaft bearing the coil may be directly drivable, wherein, in such anevent, the rotational speed of the corresponding drive should becorrespondingly adjustable.

Additional advantages of the invention are described in the followingembodiments. The following is shown:

FIG. 1 a schematic side view of a slubbing machine,

FIG. 2 a schematic side view of a slubbing machine in accordance withthe present invention,

FIG. 3 a schematic side view of a cut-out of a slubbing machine inaccordance with the present invention,

FIG. 4 a schematic side view of a cut-out of an additional slubbingmachine in accordance with the present invention, and

FIG. 5 a schematic side view of an additional slubbing machine inaccordance with the present invention.

FIG. 1 shows a schematic view of a cut-out of a slubbing machine inaccordance with the invention. This preferably comprises a deliverydevice 20 (for example, in the form of a pair of rollers) along with adownstream drafting system 19. The drafting system 19 is in turn fedwith a fiber web 2 (for example, a doubled drafting band) drawn out of acan 21 using the delivery device 20. In addition, the slubbing machinethat is shown has a spinning nozzle 3 downstream of the drafting system19 in the transport direction of the fiber web 2 and having an inletopening 4 for the fiber web 2. A vortex chamber that is not seen isarranged within the spinning nozzle 3; in this, the fiber web 2 isprovided with a protective rotation (the mode of action of the spinningposition will be described in more detail below).

Following the spinning nozzle 3, a pair of draw-off rollers 27 alongwith a winding device 6 downstream of the pair of draw-off rollers 27may finally be arranged for the rove 1 leaving the spinning nozzle 3through an outlet 5. The winding device 6 may also (as well as in thecases of the remaining figures) comprise a coil 17 for the rove 1 and adrive roller 18 driving the coil 17 through direct contact with the coilbobbin or the rove 1 spooled thereupon.

The slubbing machine in accordance with the invention need notnecessarily have a drafting system 19, as is shown or indicated in thefigures. Moreover, the pair of draw-off rollers 27 is not absolutelynecessary.

The production of the rove 1 then takes place according to a special airspinning process, which was originally employed to produce a finishedyarn. In contrast to yarn production, with the production of rove 1, itis essential that only a protective rotation is imparted to the fiberweb 2 introduced into the spinning nozzle 3, such that the resultingrove 1 continues to remain capable of being drafted for furtherprocessing in a subsequent spinning machine, for example a ring spinningmachine. However, conventional air spinning devices impart to the fiberweb 2 a rotation that is so strong that the necessary drafting followingthe yarn production is no longer possible. This is also desirable inthis case, since conventional air spinning machines are designed toproduce a finished yarn that is usually characterized by a high degreeof strength.

However, the fiber web 2 within the spinning nozzle 3 of the slubbingmachine in accordance with the invention receives only a protectiverotation. Thereby, the fiber web 2 is collected by an air flow generatedby air jets assigned to the inner vortex chamber. One part of the fibersis pulled out from the fiber web 2 at least to some extent, and woundaround the top of a spindle protruding into the vortex chamber. As aresult of the fact that the fiber web 2 is drawn out from the vortexchamber through an inlet mouth of the spindle by means of a draw-offchannel arranged within the spindle, the free ends of the fiber aredrawn in the direction of the inlet mouth and thereby looped, as wrappedfibers, around the centrally running and preferably untwisted corefibers. As a result, a rove 1 having the desired protective rotationarises, which can be drawn out of the spinning nozzle 3 through theoutlet 5.

With rove produced in such a manner, that fact that the rove 1 may haveflaw spots is disadvantageous. Generally, a flaw spot is a section ofthe rove 1, whose diameter, strength, density, weight per length orother physical dimension present for further processing lies outside ofa predefined range of tolerance. Such flaw spots must eventually beremoved in a separate step that is subsequent to the spooling onto theslubbing machine, such that the rove coil produced on the slubbingmachine cannot be delivered directly to a subsequent spinning machine,knitting machine or other textile machine processing a rove 1.

To solve this problem, it is proposed to equip the slubbing machine withan arrangement 7, to be passed by the rove 1, for detecting and removingyarn flaws 8, and to place this between the outlet 5 of the spinningnozzle 3 and a receiving device 28 receiving the drawn out rove 1, suchthat yarn flaws 8 can be detected even prior to the spooling or thedirect delivery of the rove 1 to a subsequent textile machine, or can beremoved from the rove 1.

The receiving device 28 may be formed, for example, by the windingdevice 6 that is shown. Alternatively, it is also possible to deliverthe rove 1 directly to an additional textile machine, wherein, in thisevent, the receiving device 28 may be formed by a pair of rollers, whichensures the transport of the rove 1 (leaving the device 10 for removingthe yarn flaw 8) to the subsequent textile machine. The followingdescribes by example the case in which the rove 1 is spooled onto a coil17 using the specified winding device 6.

FIG. 2 shows the basic structure of a possible embodiment of a slubbingmachine in accordance with the invention. As can be clearly seen with acomparison to FIG. 1, the slubbing machine initially has a firstconveying device 12 (such as a pair of rollers), with the assistance ofwhich the rove 1 produced in the spinning nozzle 3 is drawn out of thespinning nozzle 3. However, the rove 1 is not only drawn out, but isultimately spooled onto a coil 17 using a winding device 6. Rather,prior to spooling, for example, immediately after the exit from thespinning nozzle 3, the yarn is monitored for yarn flaws 8 using a device9 for detecting a yarn flaw 8. Thereby, optical or ultrasonic sensors(for example), which monitor, for example, the diameter of the rove 1and transmit the measured values through a wire 16 or wirelessly to acontrol unit 14, are employed; these ultimately compare the values withcorresponding target values or permissible ranges of tolerance.

After the first conveying device 12, a yarn accumulator 11 (which is tobe described in more detail), a second conveying device 13 (which inturn may be designed as a pair of rollers) and a device 10 for removinga yarn flaw 8 follow; together with the device 9 for detecting a yarnflaw 8, these form the arrangement 7 in accordance with the inventionfor detecting and removing a yarn flaw 8. Finally, the rove 1 is spooledonto a coil 17 using a winding device 6, wherein yarn flaws 8, asdescribed below, are removed prior to spooling, such that the coil 17bearing the rove 1 can be fed immediately to a textile machineprocessing the rove 1.

If a deviation from the monitored value is then recognized by the device9 for detecting a yarn flaw 8, the conveying of the rove 1 in thedirection of the receiving device 28 continues until the yarn flaw 8 isfound in the area of the device 10 for removing the yarn flaw 8 (thetime can be calculated from the conveying speed of the rove 1 and thecovered distance). Subsequently, the receiving device 28 (in the exampleshown, the winding device 6) and the second conveying device 12 arestopped, such that the section of the rove 1 having the yarn flaw 8 isfixed within the device 10 for removing the yarn flaw 8.

The rove 1 is then severed within the device 10 for removing the yarnflaw 8 by a separator or a cutter before and after the yarn flaw 8. Theremoved section of the rove 1 is finally disposed of, for example,sucked away.

Following the removal of the yarn flaw 8, the original sections of therove 1 adjacent to the yarn flaw 8 and then forming two ends of the yarnare linked to each other. Thereby, either the second conveying device 13in the transport direction (=spinning nozzle 3→receiving device 28) orthe receiving device 28 against the transport direction are driven, inorder to convey a small amount of rove 1 into the device 10 for removingthe yarn flaw 8. This can ensure that, despite the removal of the yarnflaw 8, there is sufficient rove 1 for linking the ends of the yarn. Thelink may ultimately take place through splicing, needling, rubbing,calendering, through the use of air currents or through other knownlinking methods.

In order to not then have to stop the production of rove 1 during theremoval of a yarn flaw 8, a yarn accumulator 11 is arranged between thefirst conveying device 12 (with the assistance of which the yarn isdrawn out of the spinning nozzle 3) and the second conveying device 13.This may be designed, for example, as a feeder 23 or a pneumatic yarnaccumulator 11. In the case first specified (FIG. 3), a drivable coilbobbin is provided, the circumferential speed of which during theproduction of rove approximately corresponds to the delivery speed ofthe spinning nozzle 3. The drawn out rove 1 is wrapped on the coilbobbin several times and ultimately drawn out once again through one ofthe front sides and under the interposition of a guide 22. As long asthe receiving speed of the receiving device 28 corresponds to thedraw-off speed of the first conveying device 12, the length of the rove1 wound on the coil bobbin remains constant.

If the second conveying speed is stopped for the purpose of removing ayarn flaw 8, the yarn accumulator 11 fills up, i.e. the rove 1 drawn outof the spinning nozzle 3 is wound on the coil bobbin through itsrotation, without the rove 1 being drawn out on its front side.

If the removal of the yarn flaw 8 is ended, the second conveying device13 and the receiving device 28 are once again put into operation.Thereby, the conveying speeds of the specified units can be increased inrespect of the draw-off speed of the first conveying device 12, suchthat the yarn accumulator 11 is once again emptied, to a defined minimumvalue. From such point in time, the first and second conveying devices12, 13 driven by means of the drive 15 along with the receiving device28 (i.e., in the example shown, the drive roller 18 of the coil 17) areonce again driven at “normal speed.” In other words, the quantity ofrove 1 that leaves the spinning nozzle 3 is received by the receivingdevice 28. The filling level of the yarn accumulator 11 remains constantuntil the removal of the next yarn flaw 8.

As an alternative to the feeder 23 shown in FIG. 3, a pneumatic yarnaccumulator in 11 with a recess 29 may also be used (FIG. 4). This has,for example, a vacuum chamber 24 connected to a vacuum line 26, in whichthe rove 1 in the form of a loop may be sucked in. As storage space forthe rove 1, a screen 25 may be present within the vacuum chamber 24,such that rove 1 with a length that exceeds the length of the vacuumchamber 24 can be stored on an interim basis. The pressure in the vacuumchamber 24 is finally adjustable in a manner analogous to the rotationspeed of the coil bobbin of the feeder 23 described above. In otherwords, the negative pressure increases, and the yarn accumulator 11 isthus filled, if the removal of a yarn flaw 8 is pending, and is onceagain reduced if the removal of the yarn flaw 8 has taken place, suchthat the yarn accumulator 11 may once again be emptied up to a minimumfilling level.

Finally, as a variation of FIG. 2, FIG. 5 shows an additional slubbingmachine in accordance with the invention. As can be seen in FIG. 5, thesecond conveying device 13 was omitted. Rather, the drawing out of theyarn accumulator 11 can be realized only through the drive of thewinding device 6, which in turn can take place using the drive roller 18that is shown. For example, it would thereby be possible to vary therotational speed of the coil 17, and thus the spooling speed of the rove1, by changing its drive speed (or the rotational speed of the driveroller 18).

The variation could take place in such a manner, for example, that therotational speed is selected so high that the draw-off speed of the rove1 (i.e., the length of the rove 1 spooled per unit of time) is higherthan the delivery speed (i.e., the length of the rove 1 produced perunit of time) of the spinning nozzle 3. The yarn accumulator 11 would begradually emptied at this stage.

If the filling level of the yarn accumulator 11 (monitored, for example,using a sensor) reaches a specified minimum value, the rotational speedof the coil 17 would be reduced to the extent that the draw-off speed isless than the delivery speed of the spinning nozzle 3. As a result, thefilling up of the yarn accumulator 11 would once again occur. If thefilling level exceeds a maximum value, the rotational speed of the coil17 would be increased again to its initial value, such that the emptyingof the yarn accumulator 11 would once again occur. Thus, through thecorresponding governing of the rotational speed of the coil 17 (or thedrive unit), the filling level (even during a cleaner cut, for which thecoil 17 would be at a standstill) could always be kept between thespecified limits.

In all other respects, the invention is not limited to the embodimentsthat are shown. Rather, all combinations of the described individualcharacteristics, as they are shown or described in the claims, thedescription and the figures, and to the extent that a correspondingcombination appears technically possible or sensible, are included inthe subject matter of the invention.

Reference Signs

-   -   1 Rove    -   2 Fiber web    -   3 Spinning nozzle    -   4 Inlet opening    -   5 Outlet    -   6 Winding device    -   7 Arrangement for the detection and removal of a yarn flaw    -   8 Yarn flaw    -   9 Device for the detection of a yarn flaw    -   10 Device for the removal of a yarn flaw    -   11 Yarn accumulator    -   12 First conveying device    -   13 Second conveying device    -   14 Control unit    -   15 Drive    -   16 Wire    -   17 Coil    -   18 Drive roller    -   19 Drafting system    -   20 Delivery device    -   21 Can    -   22 Guide    -   23 Feeder    -   24 Vacuum chamber    -   25 Screen    -   26 Vacuum line    -   27 Pair of draw-off rollers    -   28 Receiving device    -   29 Recess

1. Slubbing machine for producing a rove (1) from a fiber web (2),wherein the slubbing machine has at least one spinning nozzle (3) withan inlet opening (4) for the fiber web (2), wherein at least one airnozzle is assigned to the spinning nozzle (3) through which air nozzlethe air can be channeled into the spinning nozzle (3) in order to imparta protective rotation to the fiber web (2) within the spinning nozzle(3), wherein the spinning nozzle (3) has an outlet (5) through which therove (1) can be drawn out of the spinning nozzle (3), wherein theslubbing machine comprises at least one receiving device (28) arrangeddownstream of the spinning nozzle (3) in the transport direction of therove (1), particularly in the form of a winding device (6) to receivethe rove (1) leaving the spinning nozzle (3), characterized in that theslubbing machine comprises an arrangement (7), to be passed by the rove(1), for detecting and removing yarn flaws (8), the arrangement (7)being placed between the outlet (5) of the spinning nozzle (3) and thereceiving device (28). 2-15. (canceled)